# The Computer Language Benchmarks Game
# http://shootout.alioth.debian.org/
#
# originally by Kevin Carson
# modified by Tupteq, Fredrik Johansson, and Daniel Nanz
# modified by Maciej Fijalkowski
# modified by HartsAntler for RPythonic
# 2to3
import datetime
import sys, math, time

if '..' not in sys.path: sys.path.append( '..' )
import rpythonic
rpythonic.set_pypy_root( '../../pypy' )
rpy = rpythonic.RPython( 'linux' )


def combinations(l):
    result = []
    for x in range(len(l) - 1):
        ls = l[x + 1:]
        for y in ls:
            result.append((l[x], y))
    return result


PI = 3.14159265358979323
SOLAR_MASS = 4 * PI * PI
DAYS_PER_YEAR = 365.24

MASS = {
    0: SOLAR_MASS, # sun
    1: 9.54791938424326609e-04 * SOLAR_MASS, # jupiter
    2: 2.85885980666130812e-04 * SOLAR_MASS, # saturn
    3: 4.36624404335156298e-05 * SOLAR_MASS, # uranus
    4:  5.15138902046611451e-05 * SOLAR_MASS # neptune
        }

BODIES = {
    'sun': ([0.0, 0.0, 0.0], [0.0, 0.0, 0.0], [0]),


    'jupiter': ([4.84143144246472090e+00,
                 -1.16032004402742839e+00,
                 -1.03622044471123109e-01],
                [1.66007664274403694e-03 * DAYS_PER_YEAR,
                 7.69901118419740425e-03 * DAYS_PER_YEAR,
                 -6.90460016972063023e-05 * DAYS_PER_YEAR]
                , [1])
                ,

    'saturn': ([8.34336671824457987e+00,
                4.12479856412430479e+00,
                -4.03523417114321381e-01],
               [-2.76742510726862411e-03 * DAYS_PER_YEAR,
                4.99852801234917238e-03 * DAYS_PER_YEAR,
                2.30417297573763929e-05 * DAYS_PER_YEAR]
               , [2]),

    'uranus': ([1.28943695621391310e+01,
                -1.51111514016986312e+01,
                -2.23307578892655734e-01],
               [2.96460137564761618e-03 * DAYS_PER_YEAR,
                2.37847173959480950e-03 * DAYS_PER_YEAR,
                -2.96589568540237556e-05 * DAYS_PER_YEAR],
               [3]
               ),

    'neptune': ([1.53796971148509165e+01,
                 -2.59193146099879641e+01,
                 1.79258772950371181e-01],
                [2.68067772490389322e-03 * DAYS_PER_YEAR,
                 1.62824170038242295e-03 * DAYS_PER_YEAR,
                 -9.51592254519715870e-05 * DAYS_PER_YEAR],
                [4]
               ) }


SYSTEM = list(BODIES.values())
PAIRS = combinations(SYSTEM)

def advance(dt, n, bodies, pairs):
    for i in range(n):
        for (([x1, y1, z1], v1, m1index),
             ([x2, y2, z2], v2, m2index)) in pairs:
            m1 = MASS[m1index[0]]
            m2 = MASS[m2index[0]]
            dx = x1 - x2
            dy = y1 - y2
            dz = z1 - z2
            #mag = dt * ((dx * dx + dy * dy + dz * dz) ** (-1.5))
            mag = dt * math.pow((dx * dx + dy * dy + dz * dz), -1.5)
            b1m = m1 * mag
            b2m = m2 * mag
            v1[0] -= dx * b2m
            v1[1] -= dy * b2m
            v1[2] -= dz * b2m
            v2[0] += dx * b1m
            v2[1] += dy * b1m
            v2[2] += dz * b1m
        for (r, [vx, vy, vz], mindex) in bodies:
            m = MASS[mindex[0]]
            r[0] += dt * vx
            r[1] += dt * vy
            r[2] += dt * vz


def report_energy(bodies, pairs, e):
    for (((x1, y1, z1), v1, m1index),
         ((x2, y2, z2), v2, m2index)) in pairs:
        m1 = MASS[m1index[0]]
        m2 = MASS[m2index[0]]
        dx = x1 - x2
        dy = y1 - y2
        dz = z1 - z2
        e -= (m1 * m2) / math.pow((dx * dx + dy * dy + dz * dz), 0.5)
    for (r, [vx, vy, vz], mindex) in bodies:
        m = MASS[mindex[0]]
        e += m * (vx * vx + vy * vy + vz * vz) / 2.
    print("%s" % e)

def offset_momentum(ref, bodies, px, py, pz):
    for (r, [vx, vy, vz], mindex) in bodies:
        m = MASS[mindex[0]]
        px -= vx * m
        py -= vy * m
        pz -= vz * m
    (r, v, mindex) = ref
    m = MASS[mindex[0]]
    v[0] = px / m
    v[1] = py / m
    v[2] = pz / m

@rpy.standalone
def myentrypoint():
	start = time.time()
	n = 50000000
	offset_momentum(BODIES['sun'], SYSTEM, 0.0, 0.0, 0.0)
	report_energy(SYSTEM, PAIRS, 0.0)
	advance(0.01, n, SYSTEM, PAIRS)
	report_energy(SYSTEM, PAIRS, 0.0)
	print( 'Took: ', time.time()-start )

#if __name__ == '__main__':
#	t1 = datetime.datetime.now()
#	main(int(sys.argv[1]))
#	t2 = datetime.datetime.now()
#	print "Took:", t2 - t1

pak = rpy.compile()
pak.test()
pak.save( './nbody_rpythonic' )


